New York City firefighters who worked at the World Trade Center on September 11 and afterwards during the recovery have higher cancer rates than colleagues who were never called to the site, according to a study in The Lancet.

The researchers looked at the medical records of 9,583 NYC firefighters. Compared to similar workers who never worked at Ground Zero, those who did had a 19 percent higher cancer rate, and a 10 percent higher rate than a similar subset of the general population. The dust from the collapse of the towers contained several carcinogens such as dioxin, so it’s plausible that it could have fueled higher cancer rates, the authors say. Such carcinogens can both cause cancer directly by acting as mutagens on a person’s DNA, or could lead to chronic inflammation that then triggers to cancer.

Many of the rescue and recovery workers also have high levels of post-traumatic stress disorder, depression, and panic disorder, and many are still plagued by chronic ailments like asthma, acid reflux, sinusitis, according to another study in The Lancet.

One bright spot: 9/11 rescue workers were 43 percent less likely to have died in the 7 years after the attacks than the general population, possibly because those who participated in the rescue effort were healthier to begin with.